Application of H2 Control to the MIT SERC Interferometer Testbed

In this paper the experimental results of a multivariable, two input-two output, digital, H2 controller applied to the M.I.T. Space Engineering Research Center´s Interferometer testbed are presented. The testbed is a lightly damped truss structure with a disturbance rejection performance objective. To arrive for design purposes at a high fidelity model of the Interferometer testbed, a system identification technique that uses transfer function measurements was used. Next, a frequency-weighted H2 controller was designed, reduced to 38 states, and digitally implemented on the testbed. The inclusion of the frequency weight in the compensator synthesis resulted in a controller that achieved decent disturbance-rejection performance over the entire range of modeled dynamics and was gain-stabilized for stability-robustness to the higher frequency unmodeled dynamics.